Mails will not be scanned for remote server that are set in /etc/ips.remotemail. Also, you can tail /var/log/exim_mainlog file for logs. This file is used to populate logs for incoming/outgoing mails. This file also shows if the mail server IP is blacklisted and mail has been rejected by receiver server. You can also scan the mail server's IP for blacklisting. There are plenty of sites who does the lookup for you. Just google it.